Stormwater Drainage Systems Research Articles

Hydraulic Modelling Analysis for Road Stormwater Drainage Evaluation under RCPs‎ Based Rainfall Data

Road drainage systems are often-constructed utilised design approaches not incorporating process-based depictions of possible hydrological responses, resulting in insufficient systems due to infrastructural development and climate change and ultimately, increased hydrological reaction. This study assessed possible effects of precipitation intensity variation following future severe rainfall events on the current road drainage system as whether pre-climatic stormwater drainage system could withstand potentially higher discharges and the need for modified design guidelines incorporating possible precipitation intensity variations due to ‎climate change. A case study was undertaken utilising rainfall data to develop an intensity-duration-frequency (IDF) curve representing precipitation volume variations due to climate change. The peak discharge and water level were simulated using hydraulic software program SWMM 5.1 for the existing open drainage system, wherein three future potential climate scenarios, namely 2030, 2040, and 2050 were simulated based on the RCP4.5 and RCP8.5 scenarios. The simulation results showed a tremendous future precipitation increment for RCP4.5 and RCP8.5 scenarios, yielding the following values, respectively: 28.8%, ‎‎43.7% and 34.6% and 65%, 61.5% and 75.5%. Therefore, the study findings and approach implemented should be considered when detailing assessments and preserving areas are at risk of high water flows. The study concludes that the existing road drainage system's inadequacy to manage copious rainfall amounts ‎anticipated due to climate change. Therefore, the study contributes to suggest the need for developing ‎drainage system magnitude using higher return periods to mitigate flood levels ‎on urban road networks.

Modelling of Storm-water Drainage Systems in Residential Areas

All the processes that take place in an urban water system are parts of the hydrological cycle of water. Any urban development will have a negative impact on the environment, but through an optimal approach and management of rainwater, storm water drainage and pollution leakage, we prevent the degradation of these natural resources. This paper presents aspects regarding the management of the storm-water on the surfaces related to the developed residential areas within the localities, which do not have a centralized system of meteoric sewage. In most of the localities, the storm water is not collected centrally. It is being evacuated through the slopes of the lands to the gutter, where it exists and to the areas with the lowest levels of the localities. In recent years, the climate change and poor management of the storm-water in these localities led to a major risk of flooding. The paper analyses the potential flood risks of the drainage system designed for the residential area in the analysed river basin.

The Practical Influence of Climate Change on the Performance of Road Stormwater Drainage Infrastructure

The atmospheric temperature globally has risen during the last few centuries, causing global warming and climate dynamics. The impact of global warming has caused environmental effects that include increased rainfall intensity, which is recognised as the leading cause of flooding, and destruction and devastation to the surrounding environment, infrastructure, and human life. Road stormwater drainage systems are used for removing and controlling excess runoff water to the right way. However, regardless of enhanced technologies, the reliability of drainage system schemes remains a major undertaking for water and hydraulic engineers alike. In this study, a thorough evaluation of the methods employed in previous studies and research on rainfall forecasting models was undertaken. Further to that, the effect resulting from climate change on structures of drainage infrastructure is considered in addition to the methods to enhance drainage system challenges with recent models developed for advanced drainage and waterway requirements that need to be designed in consideration of climate change.

Intensity-duration-frequency curve derivation from different rain gauge records

Development of Intensity-Duration-Frequency (IDF) Curves is important for the design of various hydraulic structures such as culverts, dams, and stormwater drainage systems. In this paper, rainfall analyses are conducted to evaluate the effect of using rainfall records from different rain gauge types on IDF Curves construction. Rainfall data are collected from two recording rain gauges at Namman catchment in western Saudi Arabia. Using the available 13 years rainfall data of the two gauges, annual maxima rainfall series values are extracted and used for IDF curves computations. The rainfall gauge which is equipped with a siphon produced IDF curves with higher precipitation intensities in comparison with the other gauge. This indicates that the siphon mechanism plays an important role in decreasing the under-catchment amount of the tipping bucket gauges during heavy rainfall storms. The current study shows that the under-catchment amount of tipping-bucket rain gauges can have a significant impact on the IDF curves and the characteristics of the design storm. A correction relationship to adjust rain intensity data sets of recording rain gauges that are not furnished with siphons is proposed in this paper. The adjusted rainfall intensity values are utilized to construct reliable IDF curves.

Stress Reduction on Buried Conduits Using EPS Geofoam

In the recent years, the Kingdom of Saudi Arabia started some huge projects in the field of infrastructure development through all the Kingdom regions. Reinforced concrete pipes are considered to be a good and economic choice for sewage pipes because they are less expensive, locally produced, and environmentally safe. The use of reinforced concrete pipes is not limited to the sewage systems, but they are also used in water and oil transfer as well as in storm water drainage systems and utility tunnels throughout the Kingdom cities.

Assessment of Stormwater Drainage System for Small Urban Watershed: Case of Shambu Town, Oromia Region, Ethiopia

Stormwater runoff in a small urban watershed is one of the major challenging issues facing many countries where financial capacity is very weak to provide sufficient drainage systems. This study aims to assess the stormwater drainage system in the small urban watershed as a case study of Shambu town, Oromia Region, Ethiopia. The main objective of this study was to assess whether this excess stormwater runoff is due to hydrological change or insufficient hydraulic design of the existing drainage system in the town. The existing drainage system in this small urban watershed was analyzed by statistical analysis and the main purpose of this was to know whether the designed drainage systems were sufficient hydraulically. The existing drainage system in this small urban watershed was analyzed by statistical analysis and the main purpose of this was to know whether the designed drainage systems were sufficient hydraulically. The existing design document was taken in this analysis and field analysis also made to check whether the drainage was constructed according to the specification. The area also analyzed hydrologically by delineating the watershed using ArcSWAT and the peak discharge was computed the outlet of the watershed using Rational method. Some data such runoff coefficient and manning’s values were also generated from the watershed based on the reality on the ground. The two results from hydrological and hydraulic models were compared and that of peak discharge obtained from rational method became greater than of the Peak discharge obtained from existing drainage measurement. Therefore, in this study it was concluded that since the watershed is steep in slope, it is contributing additional runoff to this small urban watershed, additional new 50% of the existing drainage system and rehabilitation works should be implemented to modify the draining capacity of the existing scheme. Additionally, managing and improper construction alignment problem in the existing system were identified, so to control this challenge periodic cleaning and modification of slope is recommended. Keywords: Hydraulic Model, Hydrological Model, Runoff, Small Urban Watershed, Stormwater DOI: 10.7176/CER/12-9-01 Publication date: September 30 th 2020

Assessment of Stormwater Drainage System for Small Urban Watershed: A Case of Shambu Town, Oromia Region, Ethiopia

Stormwater runoff in a small urban watershed is one of the major challenging issues facing many countries where financial capacity is very weak to provide sufficient drainage systems. This study aims to assess the stormwater drainage system in the small urban watershed as a case study of Shambu town, Oromia Region, Ethiopia. The main objective of this study was to assess whether this excess stormwater runoff is due to hydrological change or insufficient hydraulic design of the existing drainage system in the town. The existing drainage system in this small urban watershed was analyzed by statistical analysis and the main purpose of this was to know whether the designed drainage systems were sufficient hydraulically. The existing drainage system in this small urban watershed was analyzed by statistical analysis and the main purpose of this was to know whether the designed drainage systems were sufficient hydraulically. The existing design document was taken in this analysis and field analysis also made to check whether the drainage was constructed according to the specification. The area also analyzed hydrologically by delineating the watershed using ArcSWAT and the peak discharge was computed the outlet of the watershed using Rational method. Some data such runoff coefficient and manning’s values were also generated from the watershed based on the reality on the ground. The two results from hydrological and hydraulic models were compared and that of peak discharge obtained from rational method became greater than of the Peak discharge obtained from existing drainage measurement. Therefore, in this study it was concluded that since the watershed is steep in slope, it is contributing additional runoff to this small urban watershed, additional new 50% of the existing drainage system and rehabilitation works should be implemented to modify the draining capacity of the existing scheme. Additionally, managing and improper construction alignment problem in the existing system were identified, so to control this challenge periodic cleaning and modification of slope is recommended.

The effects of urban vehicle traffic on heavy metal contamination in road sweeping waste and bottom sediments of retention tanks

Diffuse pollution formed during a surface runoff on paved surfaces is a source of heavy metals (HMs) of various origin. This research study indicates the connection between bottom sediments of retention tanks located on urban streams and road sweeping wastes (RSW) that migrate during surface runoff to the stormwater drainage systems with discharge to the retention tanks. Moreover, we test the primary sources of HMs in RSW by analysing the mechanical wastes (MW) produced by vehicles in order to track the relationship between car parts and HMs deposited in the retention tanks receiving the surface runoff from streets. To identify the origin of HMs diverse source tracking approaches were used: statistical methods, Pb isotope ratios, and the flag element ratio approach. MW presented a very high HMs content (max observed values in mg/kg d.w.: 10477-Zn, 3512-Cu, 412-Pb, 3.35-Cd, 226-Ni, and 633-Cr), while for RSW the HMs content was similar to the bottom sediments. The total carcinogenic risk raises concerns due to the Cr content. The source of Zn was tyre wear and traffic. Ni, Cr, Fe, and Cd were correlated to Zn and shared a common/similar origin. PCA suggested that Cu features quasi-independent behaviour. The Pb isotopic ratios of RSW indicated Pb enrichment originating from coal combustion, while the gasoline and diesel source of Pb was excluded. The Pb isotopic ratios characteristic for MW were in within the following ranges: 1.152–1.165 (206Pb/207Pb), 2.050–2.085 (208Pb/206Pb), and 2.350–2.418 (208Pb/207Pb). The complex analysis of HMs origin confirmed the motorization origin of HMs: Zn, Cr, Ni, and Cd, except Pb (coal combustion as the main source) and Cu (non-uniform origin). The results of various source tracking methods were coherent, but Pb isotope ratios alone brought important information allowing to link Pb in sediments to the atmospheric deposition of coal combustion products.

Update of intensity–duration–frequency curves for Kuwait due to extreme flash floods

Flash floods have devastating power due to their high rainfall intensities and short durations, causing serious damage to infrastructure and human life. Recent observations in the desert environment of Kuwait witnessed an increase in rainfall extremes, and the currently adopted intensity–duration–frequency (IDF) curves constructed three decades ago did not produce reliable design frequencies for existing stormwater drainage systems in residential areas. In this study, the IDF curves for the urban zone of the State of Kuwait were updated with recent records of annual maximum rainfall intensity from January 2006 to December 2017, and the Extreme Value type-I probability distribution was implemented to perform frequency analysis and estimate the design storm. The study concluded that frequent updating of IDF curves is necessary for the examined rainfall data to account for harmonic climatic variations in compliance with sunspot cycles. The updated IDF curves confirmed the pronounced increase in rainfall intensities within short durations of 5–15 min, thereby affecting water-related infrastructure in small urban catchments. Here we call for urgent action to be taken to adopt flood mitigation plans in residential areas to avoid the catastrophic impacts of extreme flash floods.

The Negative Impact of Blockage on Storm Water Drainage Network

Storm water drainage system in urban areas became a deterministic system, especially in light of the current climate changes. This system eliminates the excess water resulting from heavy rainfall, which leads to disruption of daily life. Irregular maintenance of the network system, problems appear, especially the blockage of the covers or network pipes, which affects the efficiency of the network. This study deals with the experimental investigation of blockage on storm network system and the relationship between efficiency of the system and blockage parameters. Many scenarios of blockage within grate and pipe were studied and its impact on storm system efficiency calculated. For the pipe system, two scenarios were studied; the first one is the blockage of end main pipe with relative blockage height (15%, 30%, 50%, 70%, and 90%). The second one is the blockage through the main pipe with relative blockage height (25%, 50%) and relative blockage length (33%, 67%, and 100%). For grate, the blockage is investigated with the blockage area ratio (12.5%, 25%, 37.5%, and 50%). In addition, the combined blockage of grate and pipe was studied. Finally, an equation has been created to estimate the system efficiency as a function of blockage ratios and system discharges. The results indicated that for surface blockage (12.5%, 25%, 37.5%, and 50%), the discharge efficiency decreased as the amount of blockage increased with different grate blockage by (17.8%, 19.3%, 21%, and 24.6%), respectively.

Design of Storm Water Drainage System in A Metropolitan Area

Design of Storm Water Drainage System in A Metropolitan Area

Model Hyetographs of Short-Term Rainfall for Wrocław in the Perspective of 2050

One of the most important problems while modeling stormwater drainage systems is the choice of rainfall scenario, which will take into account the real rainfall distribution over time. This problem is particularly significant due to the climate change observed in recent decades, manifested, among others, in the increase in the precipitation intensities or changes in their structure. Taking into account these forecasts is essential to safely design sewer systems and their proper operation. The work aims to verify the Euler type II standard rainfall used so far to model sewage systems in Poland and to develop the forecasted form of this pattern in the perspective of 2050. Precipitation data from measurement stations in Wrocław were used as research material. The prediction model of maximum rainfall amounts allowed to determine the forecasted increase in intensities of short-term rainfall (for the occurrence frequencies recommended by Standard EN 752:2017 for the dimensioning and modeling of sewage systems). On this basis, model hyetographs forecasted for 2050 were prepared for Wrocław. Their choice—as a future rainfall load in hydrodynamic modeling—will allow one to meet the requirements for the frequency of flooding occurrence from sewer systems and their safe operation over several decades.

Impact of urbanization on desert flash flood generation

Desert precipitations are rare but torrential, and ephemeral streams are ungauged, by which synthetic hydrograph methods become essential for flood risk assessment. This study quantifies the impact of urbanization on generating flash floods in desert watersheds. A definition of flash flood was presented in terms of the relative strength of partial storm intensity to storm design frequency for existing stormwater drainage systems. A large desert catchment was chosen to generate synthetic surface runoff hydrograph records using HEC-HMS model. The catchment characteristics were extracted using GIS tools and digital elevation data. Intensity-duration-frequency curves were used for the catchment to simulate hypothetical storms of 24-h duration for different return periods. A sensitivity analysis was performed for curve number parameter to simulate urbanization level scenarios. The results show that it is possible to employ simple models to synthesize the impact of urbanization on desert flash floods with a drastic change in hydrograph peak discharge, time to peak, and runoff volume. The former hydrograph characteristic is found to be the most sensitive, with an increase by 316% in response to increase in curve number by 10%. This finding implies that a small variation in land cover due to urbanization may significantly increase the flash flood strength and potential damage to infrastructure and human life.

Evaluating the Impact of Urban Growth on the Design of Storm Water Drainage Systems

Urban growth is one of the major causes of flooding in urban areas. This affects the runoff coefficients, which is among the most important factors that affect the design of storm water drainage systems. Changing the runoff coefficient will affect the design parameters of the drainage network, including outfall discharge, velocity, lag time and cost of construction. This study aims to assess the effect of changing the runoff coefficient due to urban growth on the design of a storm water drainage system. The hydrological models Hyfran, StormCAD and GIS are used to analyze different runoff coefficients. This study examines three zones in Dammam in the Kingdom of Saudi Arabia (KSA). The data developed from the models for the current case studies are used to develop an empirical equation to predict the max discharge for other catchments. The discharge is a function of the return period, runoff coefficient, drainage density, longest path, rainfall intensity and catchment area. To validate the developed equation, we use it to estimate the discharge in a real case study in South Korea. A comparison between the measured discharge and estimated discharge shows that the empirical equation is capable of predicting the maximum discharge for different catchments with high accuracy. Then, the validation of the models is carried out to determine the effect of the runoff coefficient on the design of a storm water drainage system in a case study in KSA. The results show that an increasing runoff coefficient due to urban growth increases the outfall discharge and velocity of storm water drainage systems, as well as affecting the cost of construction and decreasing the lag time. The cost increases by two to three times with increasing urbanization. This study provides a new perspective on the hydrologic impact of urban growth on the design of storm water drainage systems, which are essential for flood management. Moreover, the relationship between urban growth and the cost of storm drainage networks is explored, which could help decision makers to make appropriate judgements.

Cascading Flow System for Urban Drainage Design

AbstractA stormwater drainage system is an important element in the urban infrastructure network. Under the conventional concept, an urban drainage system is designed to collect and pass the extrem...

Matching analysis of investment structure and urban inundation control function of sponge cities in China

The risk of urban flood inundation has been increasing worldwide. To address this problem, the sponge city strategy has been proposed in China. This study focuses on the issue of urban flood inundation, which is a main problem that the construction of sponge cities seeks to address. The design mode of sponge city flood control and drainage systems (SCFCDSs) is examined, including source control systems (SCSs), stormwater pipe network systems (SPNSs), and over-standard stormwater storage and drainage systems (OSSSDSs). A quantitative method to evaluate flood control and drainage capacity (stormwater equivalent) of SCFCDSs is proposed and applied to quantitatively analyze the matching relationship between investment structure and inundation control function. Based on 18 pilot cities, the stormwater equivalents of the SCSs, SPNSs, and OSSSDSs account for 13.8, 57.7, and 28.6% of the stormwater equivalent of SCFCDSs on average, respectively. On the other hand, the investments in SCSs, SPNSs, and OSSSDSs account for 66.1, 15.0, and 18.9% of the total investment in SCFCDSs on average, respectively. The results show that an unbalanced investment structure and corresponding design standards along with insufficient investment in OSSSDSs are the key factors hindering the effective implementation of urban flood inundation control in sponge cities.

Lab Scale Study on Integrated GSI for Urban Drainage Systems

Urbanization grows rapidly in Malaysia and has known to have several negative impacts. As development intensifies, water runs rapidly into rivers and less filters through the soil, contributes to the congestion of the stormwater drainage system that leads to the flash flood problem. Waste and pollution transported by stormwater also posed environmental problems, thus several open drain systems were introduced to improve it. However, some of those open drainage systems contributes to more pollutions and worsened the quality of life of the urban dwellers in Malaysia. Several approaches with different concepts have been developed, including the Best Management Practices (BMPs), Low Impact Development (LID), Water Sensitive Urban Design (WSUD), Sustainable Urban Drainage Systems (SUDS), Innovative Stormwater Management and the Green Stormwater Infrastructure (GSI). This paper proposed the potential system that gives minimal impact to the environment while improving the water filtration and flood control system in the urban areas. The GSI system can effectively address water environment issues caused by traditional stormwater drainage systems. Research focuses on the development and application of an integrated GSI storage used in urban areas adapted to flood risk with the used of bio-composite material. A lab scale system was developed to study the performance of bio-composite materials and the design of inner storage as an infiltrator as runoff decelerator. Results showed that the used of rice husk and coconut fibre as an infiltrator improved the quality of rainwater. The integrated GSI that was designed to have an inner storage also elongates the surface runoff time. It is expected that the proposed design of eco-friendly integrated storage for drainage system could prevent ponding and at the same time the contaminated flow will be filtrated by the embedded bio-composite materials before entering the water bodies.

Hydrological and Hydraulic Analyses of Urban Storm Water Drainage System of Major Area of Pokhara, Nepal

The immense increase of the structural activity which decreases the pervious area of the city is alarming danger situation pertaining to drainage. Urbanization and improved area of imperviousness are the major contributors that make the existing drainage network insufficient while inadequate maintenance and haphazardly throwing rubbish on the road and drain are other issues. The major objective of the study is to analyze the hydrological and hydraulic status of the urban storm water drainage system of the major area of Pokhara City of Nepal and to compare the calculated result with existing situation, using Rehm tools HYKAS and GraPS under AutoCAD environment. The results of this study show that the size of the existing road side drains is inadequate to handle all the surface runoff. It is found that the existing situation of the drainage system is quite poor and need to be redesign or reconstruct immediately. The hydraulic load of almost all the conduit is beyond the limit assigned. The hydraulic design of the most of the drainage conduit is inadequate and re-design of the drain is essential based upon accurate flow estimation methods. This study concludes that the applicability of the current drainage system is quite poor and needs to make certain changes with their construction immediately in order to avoid any danger and adverse effect possessed by surface flooding over the road surface and other paved surfaces. The surface runoff is significantly increased compared to the situation before the construction of existing drainage system and therefore for the appropriate storm water management of the urban area of Nepal, it is critical to design the drainage system based on both hydrological and hydraulic analyses considering reliable data.

Projecting Flood-Inducing Precipitation with a Bayesian Analogue Model

The hazard of pluvial flooding is largely influenced by the spatial and temporal dependence characteristics of precipitation. When extreme precipitation possesses strong spatial dependence, the risk of flooding is amplified due to catchment factors such as topography that cause runoff accumulation. Temporal dependence can also increase flood risk as storm water drainage systems operating at capacity can be overwhelmed by heavy precipitation occurring over multiple days. While transformed Gaussian processes are common choices for modeling precipitation, their weak tail dependence may lead to underestimation of flood risk. Extreme value models such as the generalized Pareto processes for threshold exceedances and max-stable models are attractive alternatives, but are difficult to fit when the number of observation sites is large, and are of little use for modeling the bulk of the distribution, which may also be of interest to water management planners. While the atmospheric dynamics governing precipitation are complex and difficult to fully incorporate into a parsimonious statistical model, non-mechanistic analogue methods that approximate those dynamics have proven to be promising approaches to capturing the temporal dependence of precipitation. In this paper, we present a Bayesian analogue method that leverages large, synoptic-scale atmospheric patterns to make precipitation forecasts. Changing spatial dependence across varying intensities is modeled as a mixture of spatial Student-t processes that can accommodate both strong and weak tail dependence. The proposed model demonstrates improved performance at capturing the distribution of extreme precipitation over Community Atmosphere Model (CAM) 5.2 forecasts.Supplementary materials accompanying this paper appear online.

Future Assessment of Precipitation and Temperature for Developing Urban Catchment Under Impact of Climate Change

In this study, the attempt is made to investigate the impact of future climate changes related to three weather parameter maximum temperature (Tmax), minimum temperature (Tmin) and precipitation for study area were projected for two future time slice (2017–2058), and (2059–2100) from the three Global Climate Models (GCMs), CanESM2, CGCM3 and HadCM3 under different representative concentration pathway (RCPs) scenarios (RCP2.5, RCP4.5, and RCP8.5) using statistical downscaling model (SDSM). The predictor variables are downloaded from National Center for Environmental Prediction/Atmospheric Research (NCEP/NCAR) and simulations from the three Global Climate Models (GCMs), Second Generation Canadian Earth System Model (CanESM2), Canadian Centre for Climate Modelling and Analysis (CGCM3) and Hadley Centre for Climate Prediction and Research/Met Office (HadCM3) variability and changes in Tmax, Tmin and precipitation under different (RCPs) scenarios have been presented for two future time slice. The performance for three models showed maximum/minimum temperature increases in future for almost all the (RCPs) scenarios. Also precipitation of the entire catchment was found to increasing trends for all scenarios. In case of HadCM3 model, under RCP8.5 scenarios for the period (2017-2058), changes in max temperature, min temperature, and precipitation are forecasted as 0.72 °C, 1.42 °C, and 2.82 mm and for the period (2059-2100) are 1.16 °C, 2.14 °C, and 6.85 mm.The results obtained from HadCM3 model is higher side as compared with CanESM2, CGCM3.These results can provide understanding of the hydrologic role of future climate change scenarios, which is essential for probable impacts of climate change for planning and management of appropriate choice for designing the storm water drainage system and infrastructure for newly growing urbanization under climate change are of great concern to hydrologists, water managers, and policymakers.